/**
 * 获取页面的高度、宽度
 * @author Libra
 */

function getPageSize() {
        var xScroll, yScroll;
        if (window.innerHeight && window.scrollMaxY) {
            xScroll = window.innerWidth + window.scrollMaxX;
            yScroll = window.innerHeight + window.scrollMaxY;
        } else {
            if (document.body.scrollHeight > document.body.offsetHeight) { // all but Explorer Mac    
                xScroll = document.body.scrollWidth;
                yScroll = document.body.scrollHeight;
            } else { // Explorer Mac...would also work in Explorer 6 Strict, Mozilla and Safari    
                xScroll = document.body.offsetWidth;
                yScroll = document.body.offsetHeight;
            }
        }
        var windowWidth, windowHeight;
        if (self.innerHeight) { // all except Explorer    
            if (document.documentElement.clientWidth) {
                windowWidth = document.documentElement.clientWidth;
            } else {
                windowWidth = self.innerWidth;
            }
            windowHeight = self.innerHeight;
        } else {
            if (document.documentElement && document.documentElement.clientHeight) { // Explorer 6 Strict Mode    
                windowWidth = document.documentElement.clientWidth;
                windowHeight = document.documentElement.clientHeight;
            } else {
                if (document.body) { // other Explorers    
                    windowWidth = document.body.clientWidth;
                    windowHeight = document.body.clientHeight;
                }
            }
        }       
        // for small pages with total height less then height of the viewport    
        if (yScroll < windowHeight) {
            pageHeight = windowHeight;
        } else {
            pageHeight = yScroll;
        }    
        // for small pages with total width less then width of the viewport    
        if (xScroll < windowWidth) {
            pageWidth = xScroll;
        } else {
            pageWidth = windowWidth;
        }
        arrayPageSize = [pageWidth, pageHeight, windowWidth, windowHeight];
        return arrayPageSize;
    }